Answer: (4/3)πr³.
- A (2/3)πr³
- B (4/3)πr³
- C (1/3)πr³
- D πr³
Correct answer: B. (4/3)πr³
Explanation: Rotation of semicircle about diameter gives full sphere. Volume = (4/3)πr³.
Three standard 3D solids and their key formulas: a cylinder's volume scales with the full height, a cone's volume is exactly one-third of the cylinder with the same base and height, and a sphere's volume and surface area both follow distinct r-based formulas worth memorising separately.
Concept context
Perimeters, areas, and volumes of 2D and 3D shapes